Nine-hour pump claims UK record

Product quality was a key factor in setting what is thought to be UK concrete pumping record on London’s Crossrail project. The concrete was pumped 1.3 kilometres from Plumstead to Woolwich for the formation of the invert of the 6.2 metre diameter tunnel on section C310 of the huge rail project, which will connect east and west London. The final 112 cubic metre pour took nine hours to complete.

Although concrete has been pumped greater distances, it has involved multiple stages. Specialist sub-contractor Kelly Formwork and pump supplier Schwing Stetter are convinced it was the longest ‘single push’ ever completed in the UK.

Jasen Gauld, national accounts technical manager, said: “The concrete was supplied from our refurbished Silvertown plant on the Thames and pumped with a Schwing 3500 static pump connected to a 125mm pipeline. It took 90 minutes for the concrete to reach the end of the line and at its peak there would have been 16 cubic metres of concrete weighing 38 tonnes in the pipeline.”

He said the specified C32/40 mix design was critical to the success of the project. Cement from the Ketton works was blended with Regen from Purfleet in a 60:40 ratio.

Kelly started work at the Plumstead tunnel mouth and carried out 18 pours in total, extending the pipeline each time.